It's possible the headset is overheating and thermal throttling. What is your resolution in the advanced video settings, and your autofocus accuracy in the user settings? Maybe try lowering those values to see if it helps. Setting sharpness to 0 will also help with performance. Also, charging your headset while you're using the app will increase the thermal load, so it increases the chance of the headset thermal throttling. I haven't run into this issue myself, so it might vary from headset to headset.